September 2018

09/20/2018

He is concentrating so much that he might not notice the coffee smell.... Photo: baranq/Shutterstock

At times, we've all been so engrossed in a task that we've lost awareness of our surroundings. Maybe you didn't hear someone calling your name when you were finishing your paper, or maybe you missed the oven timer when you were reading that mystery book. Now researchers Sophie Forester and Charles Spence have reported that concentration impacts our sense of smell. Here's how the research was described on the APS website:

They set up a room to be distinctively aromatic, hiding three small containers of coffee beans around the room overnight. Over the course of two experiments, they led 40 college students into the room one at a time to perform a tough visual-search task on a computer, finding the letter “X” or “N” in a circle of similar-looking letters (“W,” “M,” “K,” “H,” “Z,” and “V”). 40 other students completed an easier version of the same task; searching for the letter “X” or “N” among a circle of lowercase “o”s. [Students had been randomly assigned to either the difficult or easy task.]

The experimenters then took the students into another room and asked them some follow up questions that grew increasingly leading :

“Describe the room you just completed the task in. Try to describe it using all of your senses.”

“Did you notice any odors in the room, if so what?”

“Could you smell coffee in the room?”

Students assigned to the difficult search task were far less likely to report having picked up the aroma (25% of participants said they noticed a coffee smell) compared to the participants assigned to the easy task (60%-70% percent of participants). When the experimenters led the students back into the test room, all of them said they could smell it. Some of them even commented that the room smelled like a cafe.

Questions

What kind of study was this--experimental or correlational? How do you know?

What was the independent variable? What was the dependent variable?

Think about construct validity: What do you think of the way they measured their dependent variable? Is this a good measure?

Now think about statistical validity: How large does this effect seem to be? Take another look at the results and make a comment on the practical effect size.

What about external validity? To whom might these results generalize? Do you think the pattern for coffee and letter detection might generalize to other smells? To other tasks?

Now consider internal validity. The authors claim that it was concentration that caused people to not notice the smell. Can you think of any confounds in this design?

09/10/2018

College graduates were more likely than those who'd not been to college to report they are "smarter than average." Is their perception overconfident, or not? Photo: PeopleImages/Getty Images

It seems to be conventional wisdom that people are overconfident in their own abilities. People tend to think they are nicer, smarter, and better looking than most other people. But what's the evidence? The scientist-authors of this Wall Street Journal summary explain,

The claim that "most people think they are smarter than average" is a cliche of popular psychology, but the scientific evidence for it is surprisingly thin. Most research in this area has been conducted using small samples of individuals or only with high school or college students. The most recent study that polled a representative sample of American adults on the topic was published way back in 1965.

The authors, Patrick Heck and Christopher Chabris, worked with a third colleague.

..[W]e conducted two surveys: one using traditional telephone-polling methods, the other using internet research volunteers. Altogether we asked a combined representative sample of 2,821 Americans whether they agreed or disagreed with the simple statement "I am more intelligent than the average person."

Here are some of the results:

We found that more than 50% of every subgroup of people -- young and old, white and nonwhite, male and female -- agreed that they are smarter than average. Perhaps unsurprisingly, more men exhibited overconfidence (71% said they were smarter than average) than women (only 59% agreed).

Perhaps "overconfidence" is really accuracy? Consider this pattern of results:

In our study, confidence increased with education: 73% of people with a graduate degree agreed that they are smarter than average, compared with 71% of college graduates, 62% of people with "some college" experience and just 52% of people who never attended college.

The accessible Wall Street Journal summary is paywalled, but the original empirical publication is open-access in PLOS One.

Questions

a) What kind of study was this? Survey/poll? Correlational? Experimental? What are its key variables?

b) The authors found that more than 50% of every subgroup of people considered themselves smarter than average. Why is this result a sign of overconfidence?

c) The authors of this piece state that their combined sample was "representative". Re-read the section on how they got their sample and then make your own assessment--is the sample representative? (i.e., how is its external validity?). What population of interest do they intend to represent?

d) Sketch a graph of this result:

73% of people with a graduate degree agreed that they are smarter than average, compared with 71% of college graduates, 62% of people with "some college" experience and just 52% of people who never attended college.

e) In concluding their article, the authors wrote, "Our study shows that many people think they are smarter than they really are, but they may not be stupid to think so." What do you think? To what extent does this study's results support this conclusion?

e) Ask a question about this study's construct, internal, external, and statistical validity.

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